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Tuning Interactions between Dissimilar Surfaces by Polyelectrolytes

English title Tuning Interactions between Dissimilar Surfaces by Polyelectrolytes
Applicant Borkovec Michal
Number 140327
Funding scheme Project funding
Research institution Département de Chimie Minérale et Analytique Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Physical Chemistry
Start/End 01.06.2012 - 31.05.2015
Approved amount 657'480.00
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Keywords (7)

particle heteroaggregation; polyelectrolytes; surface forces; adsorption; particle deposition; atomic force microscopy; light scattering

Lay Summary (English)

Lay summary

The control of interaction forces between particles in aqueous suspensions is essential in numerous industrial processes (e.g., water treatment, papermaking, food processing) and products (e.g., drugs, paint, glues). While substantial amount of information is available concerning interactions between similar particles, frequently, the essential interactions involve dissimilar particles. Important examples involve clay and iron oxide particles suspended in natural waters or calcium carbonate particles and cellulose fibers in paper-manufacturing slurries. Much less is known about the interactions in these situations, and the present project will address precisely such situations. Particle properties will be tuned by adsorption of polyelectrolytes. State-of-the-art techniques will be used to probe interactions between dissimilar particles, including light scattering, electrophoresis, and direct force measurements with the atomic force microscope. The experimental results will be confronted with current theories of interaction forces with the aim to indentify the principal mechanisms. This research is expected to have impact in several applied fields, particularly, in the development of improved strategies for water purification, environmental remediation, or drug delivery.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants



Group / person Country
Types of collaboration
Alberto Morpurgo, University of Geneva Switzerland (Europe)
- Research Infrastructure
- Exchange of personnel
Ger Koper, Delft University of Technology Netherlands (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Christophe Labbez, Université de Bourgogne France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Exchange of personnel
Zbigniew Adamczyk, Polish Academy of Science Poland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Exchange of personnel

Associated projects

Number Title Start Funding scheme
124383 Interactions between Charged Surfaces Triggered by Multivalent Ions 01.06.2009 Project funding
159874 Polyelectrolytes near like-charged substrates in the presence of multivalent ions 01.06.2015 Project funding
128680 Polyelectrolytes and Interfaces Investigated by Atomic Force Microscopy 01.12.2009 R'EQUIP
150631 Direct force measurements with combined total internal reflection and atomic force microscopy 01.12.2013 R'EQUIP
126053 Single-molecule mechanics of dendronized polymers 01.03.2010 NRP 62 Smart Materials
136191 Designing Interactions across Interfaces in Ionic Liquids 01.01.2012 Sinergia


This project will investigate how heteroaggregation and deposition of colloidal particles is influenced by polyelectrolytes and complete these investigations by direct measurements of the underlying surface forces. Heteroaggregation will be probed by multi-angle light scattering and deposition with optical reflectivity. Forces between dissimilar particles and surfaces will be measured with multi-particle colloidal probe technique based on the atomic force microscope (AFM). The new aspect of this work is that force measurements will be carried out with exactly the same particles used as for heteroaggregation or deposition studies. Charge regulation effects will be investigated in detail, since they influence interaction forces in asymmetric systems substantially. When one of the surfaces is close to neutral but the other one charged, charge regulation effects even determine whether forces are attractive or repulsive. Detailed experimental data will be obtained for this regime and compared with theoretical predictions. Moreover, regulation behavior of the surfaces is expected to be sensitive to the presence and nature of the adsorbed polyelectrolytes. These investigations will equally address interactions between surfaces due to lateral surface charge heterogeneities and bridging, and especially investigate their role for dissimilar surfaces. This work will have implications on industrial processes involving suspension stabilization, separation processes, or filtration.